Waterpower machine

ABSTRACT

A waterpower machine has a vertical cylinder, the lower end of which is open, a piston which is vertically reciprocable in the cylinder, a water chamber provided at the lower end of the cylinder wherein the water chamber has a water inlet and a water outlet, an inlet valve for controlling water inflow into in the water chamber through the water inlet, and an outlet valve for controlling water outflow from the water chamber through the water outlet. Both the water inlet and the water outlet are opened towards the periphery of the water chamber over the major portion of the water chamber circumference. The water inlet is at a different level from that of the water outlet. The inlet valve and the outlet valve comprise respective ones of a pair of annular valve members which are concentric with one another and with the cylinder and axially moveable between a closed position and an open position.

BACKGROUND OF THE INVENTION

This invention relates to a waterpower machine. More particularly, theinvention relates to a waterpower machine which, although not solimited, is particularly well suited for use in waterpower stations inwhich energy is extracted from water streams or other sources of waterhaving a relatively small fall and, possibly, also a small rate of flow,such as hydroelectric power stations in which the extracted power is oneor a few thousand kW or lower, down to a few hundred kW.

It has been difficult to achieve adequate profitability of waterpowerstations having a power output of such a relatively low magnitude,because the cost of installation has been too high in relation to thecommercial value of the produced power.

There are numerous watercourses which offer possibilities of extractingpower in the above-mentioned range, especially power in the lowerportion of that range. Accordingly, there is a need for waterpowermachines which can be used for constructing cheap waterpower stationsfor that power range.

SUMMARY OF THE INVENTION

An object of the invention is to provide a waterpower machine whichthoroughly answers this need, that is, a waterpower machine which issimple and inexpensive and does not require extensive construction workfor its installation.

The invention is concerned with a piston-type waterpower machine and,more specifically, a waterpower machine of the kind defined in theprecharacterising part of the independent claim. A waterpower machine ofthis kind is disclosed in U.S. Pat. No. 5,325,667.

In accordance with the invention, the above-stated and other objects areachieved by constructing a waterpower machine of this kind as set forthin the characterising part of the independent claim. The dependentclaims define preferred embodiments.

The waterpower machine according to the invention is useful not only asan energy-producing machine or hydraulic motor but also as anenergy-consuming machine or pump. However, it will be described withparticular reference to its use as a hydraulic motor.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in greater detail below with referenceto the accompanying diagrammatic drawings which show embodiments by wayof examples.

FIG. 1 is a diagrammatic view, partly in a vertical section, of twowaterpower machines according to the invention positioned side by sideand connected with a common power extraction device in a power supplysystem;

FIG. 2 is a diagrammatic plan view of the waterpower machines shown inFIG. 1;

FIGS. 3 and 4 are views drawn to a larger scale and showing one of thewaterpower machines of FIG. 1 in two different phases of an operatingcycle;

FIGS. 5 and 6 are views corresponding to FIGS. 3 and 4 and showing amodified embodiment;

FIGS. 7 and 8 show another embodiment, namely a double-acting waterpowermachine which, apart from being double-acting, is generally similar tothe embodiment of FIGS. 5 and 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The waterpower station diagrammatically shown in FIGS. 1-4 comprises twoidentical hydrostatic waterpower machines 11A and 11B operating inpush-pull fashion, and a common power extraction device 12 which isconnected to the waterpower machines through hydrostatic transmissionscomprising double-acting hydraulic cylinders and fluid transmissionlines interconnecting the cylinders.

A base body 13 which is common to both machines 11A and 11B andpreferably constructed mainly from concrete, defines for each machine agenerally circular-cylindrical, upstanding water chamber 14 having aperipheral water inlet 15 and a likewise peripheral water outlet 16. Thevertical central axis of the water chamber 14 is designated by L.

In the illustrated embodiment, the water inlet 15 is located at theupper portion of the water chamber 14, while the water outlet 16 islocated at the lower portion. Both the water inlet 15 and the wateroutlet 16 are constructed such that they are open towards the peripheryof the water chamber along a major portion of, or the entire,circumference of the water chamber, and they have a substantial height.Accordingly, their throughflow area is very large.

The level of the water flowing to the waterpower machines which may be,for example, water from a stream or tidewater, is presumed to be higherthan the highest portion of the water inlet 15, and the water outlet 16is arranged such that the water in the water chamber 14 can escape fromit through the open water outlet without encountering any substantialresistance to flow.

Positioned above and concentric with the water chamber 14 are anupstanding sheet-steel cylinder 17 and a piston 18 which is axiallymovable in the cylinder between a lower position approximately levelwith the water inlet 15 and an upper position. In FIG. 1, the piston inmachine 11A is in its lower position, and the piston in machine 11B isin its upper position. The piston 18 comprises a base plate 18A, made ofconcrete for example, and a high collar 18B extending upwardly from theperiphery of the base plate.

The piston 18 is connected with the piston rods of a plurality of, threefor example, double-acting hydraulic cylinders 19 positioned above thebase plate so that the pistons of these cylinders are reciprocatedvertically in unison with the piston 18. The cylinders 19 belong to thepower extraction device 12 by means of which useful power is extractedin a manner to be described.

For controlling the water inflow from the water inlet 15 into the waterchamber 14, an inlet valve 20 is provided which comprises a valve member21 in the shape of a sheet-steel ring concentric with the cylinder 17and having a slightly larger diameter. A plurality of, three forexample, double-acting hydraulic cylinders 22 with associated pistonrods are provided to actuate the valve member. By means of thesecylinders the valve member 21 can be displaced vertically between anupper open position (shown in the left machine 11A in FIG. 1), in whichthe inlet 15 is fully open so that a substantially unobstructed inflowof water into the water chamber 14 is possible, and a lower, closedposition, in which the inlet is blocked so that inflow of water into thewater chamber is substantially blocked.

For the control of water outflow from the water chamber 14 through thewater outlet 16, there is provided in a similar fashion an outlet valve23 which comprises a valve member 24 in the shape of a sheet-steel ringconcentric with the cylinder 17. This ring is rigidly connected with thecylinder 17 through the intermediary of rods or bars 25 or otherconnecting elements which define flowthrough openings for water comingfrom the inlet 15. The valve member 24 has substantially the samediameter as the cylinder 17 and accordingly forms a downward extensionof the cylinder, which extension is positioned a short radial distanceinwardly of the inlet valve member 21.

For actuation of the outlet valve member 24 a plurality of, three forexample, double-acting hydraulic cylinders 26 are provided, the pistonrods of which are connected with the cylinder 17. By means of thesecylinders, the cylinder 17 and thereby also the valve member 24 can bedisplaced vertically between an upper, open position (shown in themachine 11B to the right in FIG. 1) in which the water outlet 16 isfully open so that unimpeded water flow out of the water chamber 14 ispossible, and a lower, closed position (shown in the machine 11A to theleft in FIG. 1), in which the outlet 16 is blocked so that substantiallyno flow of water out of the water chamber is possible.

As is best shown in FIGS. 3 and 4, the inlet valve member 21 is guidedby a guide 26 on the base body 13 directly above the inlet 15 and by aguide positioned on the lower portion of a surrounding outer support 27which extends upwardly from the base body 13. The cylinder 17, which ispositioned inside the inlet valve member 21, is guided by the inner sideof the valve member 21 and by a guide 28 positioned on the upper portionof the support 27. The valve member 24 is guided by the wall of thewater chamber 14, between the inlet 15 and the outlet 16, and, throughthe intermediary of the bars or rods 25 and the cylinder 17, by theinner side of the valve member 21. The piston 18, finally, is guided onthe inner side of the cylinder 17 by a guide 29 which is positioned at alevel above the piston base plate 18A.

It should be noted that the water inlet need not necessarily be situatedhigher than the water outlet as is shown in the drawings but may verywell be at a lower level. Preferably, however, one is directly above theother.

In carrying out the invention, it is not necessary to meet strictrequirements on the sealing between the various guides and thecomponents cooperating with them. A certain constant leakage past theguides causes no major disadvantages and can readily be accepted.Consequently, the various components need not be made to precisedimensions or fit together very accurately. If a substantially completefreedom of leakage should nevertheless be desired, bellows, rollingdiaphragms and other suitable sealing elements can be provided to ensuretightness. It may then also be necessary to provide venting means.

As is readily seen from FIGS. 3 and 4, the valve members 21 and 24, thecylinder 17 and the piston 18 may readily be mounted after the base body13 has been constructed. Initially, the lower part of the support 27 ismounted on the base body 13 and the valve member 21 is then brought inposition. Thereupon, the upper part of the support 27 is attached, andthe cylinder 17 with the valve member 24 is brought in position. Thepiston 18 is then lowered into the cylinder 17 and the variouscomponents are connected with the piston rods of the cylinders 19, 22and 26. Dismantling can be accomplished in a correspondingly simplemanner.

The power extraction device 12 comprises a crankshaft 30 with a flywheel31 and a generator or other load (not shown). Two cranks 32, 33 and fourcams 34-37 are provided on the crankshaft. The cranks and the cams aredrivingly connected with respective ones of six double-acting hydrauliccylinders 38-43. Conduits 44, 45 connect the cylinders 38, 39 withrespectively the cylinders 19 of the machine 11A and the cylinders 19 ofthe machine 11B to drive the crankshaft 30 through the intermediary ofthe respective cranks 32 and 33, which are angularly offset 180° fromone another.

Conduits 46-49 connect the other four cylinders 40-43 with the valveactuating cylinders 22 and 26 in the manner illustrated in FIG. 1 todisplace the valve members 21 and 24 in timed relationship with themovements of the piston 18 of each of the machines 11A and 11B.

The operation of the illustrated waterpower supply system is as follows:

In the initial position shown in FIG. 1, the piston 18 of the machine11A is in its lower end position, and the inlet valve member 21 has justopened the water inlet 15 so that water can flow into the water chamber14, while the outlet valve member 24 has just closed the outlet 16. Inthe machine 11B the situation is the opposite. That is, the piston 18 isin its upper end position and the inlet valve member 21 has just closedthe inlet 15 to prevent continued inflow of water into the water chamber14, while the outlet valve member 24 has just opened the outlet 16 sothat water can flow out of the water chamber.

In the machine 11A, the inflowing water pushes the piston 18 upwards,and the cylinders 19 of this machine drive the crankshaft 30 in a givendirection by means of the cylinder 39 of the power extracting device 12.In the machine 11B, the piston 18 moves downwards under its own weightand the cylinders 19 of the machine drive the crankshaft in the givendirection by means of the cylinder 39.

When the piston 18 of the machine 11A reaches its upper end position,the cam 37 actuates its cylinder 43 so that this cylinder causes thecylinder 22 of the machine to move the inlet valve member 21 downwardsto closed position. Similarly, the cam 36 actuates its cylinder 42 sothat this cylinder causes the cylinders 26 of the machine to move theoutlet valve member 24 upwards to open position. The machine 11A therebytakes the position in which the machine 11B was at the commencement ofthe phase of the operation being described.

When the piston 18 of the machine 11B reaches its lower end position,the cam 35 actuates its cylinder 41 so that this cylinder causes thecylinders 22 of the machine to move the inlet valve member 21 to openposition. Similarly, the cam 34 actuates its cylinder 40 so that thiscylinder causes the cylinders 26 of the machine to move the outlet valvemember 24 to closed position. The machine 11B thereby takes the positionin which the machine 11A was at the commencement of the phase of theoperation being described.

Both machines 11A and 11B then carry out the second half of theoperating cycle. For each machine this half-cycle corresponds to thealready described half-cycle of the other machine.

Suitably, the weight of the two pistons 18 is adjusted (e.g. using aballast) such that both machines provide approximately equalcontributions to the impulse fed to the crankshaft during eachhalf-cycle.

The waterpower supply system shown by way of example only comprises twomachines but it is within the scope of the invention to form it from alarger number of machines which preferably operate with a phase-shiftcorresponding to their number. Naturally, it is also possible, althoughnot preferable, to have only a single machine. If only one machine isprovided, it is preferable to balance its piston such that it feedsapproximately equal impulses to the power extraction device during thedownward motion and the upward motion.

On the upstream side of the inlet valves it may be preferable to providea water accumulator which takes up the pressure fluctuations on theupstream side which might result as a consequence of the total flow ofwater into the water chambers not being fully constant over theoperating cycle. Such an accumulator may be preferable especially whenthe waterpower supply system only comprises one or two machines whichare supplied with water through pipelines. In FIG. 2 such an accumulatoris indicated at 50 near each machine 11A and 11B. The accumulator may bea space which extends upwardly from the water inlet 15 and is in opencommunication with it but which is otherwise closed so that the waterinflow into the accumulator takes place against a gradually increasingcounterpressure caused by the compression of air in the accumulatorspace.

In the drawings the crankshaft device 12 is shown as being the solepower extraction device. However, it is also possible to extract only aportion of the useful power by means of the device 12. A smaller orlarger portion can be intermittently or continuously extracted by othermeans.

The illustrated power extraction device 12 is a device for positivelysynchronizing or timing the actuation of the inlet and outlet valveswith the movements of the piston 18, that is, the element the movementsof which produce the useful power, and it may also be used as such asynchronizing or timing device in waterpower machines which are of thekind initially described but are not constructed in accordance with theinvention. Accordingly, this device is useful independently of thewaterpower machine according to the invention.

The cams 34-37 on the crankshaft of the power extraction device may beregarded as a mere example of indicators of angular position of thecrankshaft. Naturally, such position indicators may be replaced withother types of position indicators or sensors which control the inletand outlet valves via a suitable servo system.

The embodiment shown in FIGS. 5 and 6 differs from that shown in FIGS.1-4 in that the inlet valve member and the outlet valve member areconstituted by a single tubular part, designated by 24A, which isrigidly connected with the cylinder 17.

In this embodiment, the inlet valve and the outlet valve are thusconstrained for simultaneous actuation, so that for a certain timeduring each cycle of operation both the water inlet and the water outletare partially open at the same time and consequently allow some water toflow through the outlet without contributing to the useful work. On theother hand, a separate inlet valve with associated actuating and controlmeans can be dispensed with.

In the double-acting waterpower machine shown in FIGS. 7 and 8 the waterchamber 14 is subdivided into a lower chamber section 14A and an upperchamber section 14B. Moreover, the cylinder 17 is disposed between thesechamber sections and is in open communication with them. In acorresponding manner the water inlet and the water outlet are subdividedinto a lower section 15A and 16A, respectively, and an upper section 15Band 16B, respectively. The common inlet and outlet valve member 24A issubdivided into a lower section 24AA and an upper section 24AB.

As is readily apparent from FIGS. 7 and 8, the two sections of themachine operate in push-pull fashion so that the embodiment of FIGS. 7and 8 combine in a single machine two machines of the construction shownin FIGS. 5 and 6.

The embodiment of FIGS. 7 and 8 also differs from the precedingembodiments in that the piston 18 has a tubular piston rod 50 which isguided on a central, stationary column 51 instead of being guided at theperiphery against the inner side of the cylinder 17. A similar guidingsystem may be used for the valve members as well.

Various movable parts of the waterpower machine according to theinvention, such as the peripheral edge of the piston and those edges ofthe valve members which shall seal against the base body, may beprovided with resilient lips or the like which readily adapt toirregularities of parts with which they cooperate, such as pebbles, bitsof wood etc. entering the machine with the water flowing through it.Moreover, if desired, the water chamber can be provided with windows,e.g. in the base body or in the piston, permitting light to enter thewater chamber.

The waterpower machine according to the invention can be erectedstanding by itself surrounded by water so that water can enter the inletfrom all directions and also escape through the outlet in alldirections, that is, so that both the inlet and the outlet are "exposed"to the surrounding water on all sides.

What is claimed is:
 1. A waterpower machine comprising:a cylinder (17);a piston (18) which is reciprocally movable in the cylinder; a waterchamber (14) having a central axis (L), a water inlet (15) and a wateroutlet (16), the water chamber communicating with the cylinder and thewater inlet and the water outlet being arranged about the central axisof the water chamber and open towards the water chamber over at leastthe major portion of the circumference thereof; valve means (20,23)associated with the water inlet and the water outlet for controllinginflow of water into and outflow of water from the water chamber; andcharacterised in that the water inlet (15) and the water outlet (16) arespaced apart in the direction of the central axis (L).
 2. A waterpowermachine according to claim 1, characterised in that the water inlet (15)and the water outlet (16) are spaced apart vertically.
 3. A waterpowermachine according to claim 2, characterised in that the water inlet (15)and the water outlet (16) are positioned such that one is situatedsubstantially directly vertically above the other.
 4. A waterpowermachine according to claim 2, characterised in that the water inlet (15)is at a higher level than the water outlet (16).
 5. A waterpower machineaccording to claim 1, characterised in that the valve means comprises aninlet valve member (21) and an outlet valve member (24), both of whichare annular and concentric with one another and with the cylinder (17)and axially movable between opened and closed positions.
 6. A waterpowermachine according to claim 5, characterized in that one of the valvemembers, is connected with a tubular member which forms the cylinder(17) and is axially movable together with said one valve member, and inthat the water inlet (15) communicates with the water chamber (14) byway of passages provided between the tubular member and said one valvemember.
 7. A waterpower machine according to claim 6, characterised inthat the other valve member, surrounds the tubular member (17).
 8. Awaterpower machine according to claim 6, characterised in that the othervalve member (21) is also connected with the tubular member forming thecylinder (17) and is axially movable together with the tubular memberand said one valve member (24).
 9. A waterpower machine according toclaim 1, characterised in that the water chamber (14) comprises twochamber sections (14A,14B) which communicate with respective ends of thecylinder (17) and are associated with a respective section (15A,15B) ofthe water inlet and a respective section (16A,16B) of the water outlet,the water inlet section and the water outlet section associated with thesame water chamber section being spaced apart in the direction of thecentral axis (L).
 10. A waterpower machine according to claim 1, inwhich the piston (18) is coupled with a driven power extraction device(12), characterised in that the power extraction device comprises acrankshaft (30) which is driven by the piston (18) via a firsthydrostatic transmission (19,38,39,44,45) and coupled with actuatingmeans (22,26) of the valve members (20,23) via a second hydrostatictransmission (40-43, 46-49).
 11. A hydrostatic waterpower machinecomprising:a reciprocally movable force generating member (18); inlet(20) and outlet (23) valve means; a power extraction device (12) drivenby the force generating member (18); and a device (22-26) for actuatingthe inlet and outlet valve means in synchronism with the reciprocatorymovement of the force generating member (18); characterised in that thepower extraction device (12) comprises a crankshaft (30) which is drivenby the force generating member via a first hydrostatic transmission(19,38,39,44,45) and coupled with actuating means (22,26) of the valvemembers (20,23) via a second hydrostatic transmission (40-43, 46-49).